Ambrosio's Unaplex II: Room within a Room Build

**tjambro** · **04-15-09, 06:06 AM**

Thanks guys. It would have been nice not to have to spray paint them, but oh well, it's not that big of a deal.

**tjambro** · **05-03-09, 08:58 PM**

I'm making progress but it is most definitely slow.

First, as most, I determined that I hate mudding and taping...fortunately, I only have to worry about the ceilings since fabric will cover the walls. I got the ceiling in the theater and sound lock room taped, mudded and painted. I went to Home Depot looking for the infamous "mouse ear black" but did not find it. I found Behr Black Suede which looks very, very black. For a picture of it, look below where I describe my soffit progress, or should I say lack thereof.

This weekend, I didn't work on the room much but what I did was good and bad. Here's the beginning of the good part:

This is a photo of the inside side of the ductboard that I am going to put in the soffits for my ventilation. Due to low ceiling height (7'3") I am only having soffits with a finished depth of 6" so flex duct would not fit. I decided to give ductboard assembly a shot. With the Amcraft tools sitting on the ductboard, the job is fairly easy.

Here's a photo of the duct, ready to place in the soffits:

The ductboard comes as a 1" thick 4x10' sheet. This is a full sheet folded into a duct that is just over 5" tall. The finished area is about 17.5" x 3" giving me an area of 52.5 square inches which is about the size of a 8" round flex vent which is what I was shooting for. I have two 8" Fantech inline fans that will move the air in and out of the theater.

Here's the "two steps back" I was talking about:

This is the beginning of my soffit build. This photo isn't all that bad, I was too embarrassed to post a picture that shows how crooked this thing really is. I was afraid that this would happen. The soffits are going to be 28" wide, to fit the ductboard and my can lights, and will be covered with 3/4" ply that I plan on staining or dying (analin dye?) black. I was concerned that any small mishap on my part would make the soffits look crooked due to the width but my measurements actually turned out good. My room is not square so I didn't want to build the soffits off ceiling or floor measurements so I bought a cheapo laser level that made affixing the 2x2's to the wall a fairly easy project.

My mistake was thinking that Lowe's sold wood that was anywhere near straight. I tossed aside some really bad 2x2's but even the ones that looked remotely straight were not when they were not affixed directly to the wall or ceiling. My second mistake was thinking I could affix crooked 2x2's to the ceiling with 5" lag bolts (remember I have 2" of sheetrock to go through) with liquid nails on the crooked 2x2 without smearing it on my newly painted ceiling. Oh well, what's done is done...

I was able to put cross members in place to straighten the soffit out somewhat but I can't do that where an actual duct will go because there won't be enough clearance for the duct to fit in the soffit. I think I will see if I can get some straight 2x2's from a local lumber supply place instead of the big box stores. I ran into the same problem with the 3/4" birch ply I bought for the soffits. I started off with Lowe's birch ply for $42.88/sheet but after bringing it home I knew I wouldn't be happy with all the knots so I returned it and got 10 sheets of much better birch at the local lumber yard for $62.xx/sheet. More expensive, but definitely better wood. Hopefully, the local lumber yard will have straight lumber!

I'm a bit bummed, but it will all be worth it in the end.

**Ted White** · **05-04-09, 11:42 AM**

Hi Tom,

So you're attaching the soffit frame to the decoupled walls and ceiling? Are you going to double drywall the soffit face?

**tjambro** · **05-04-09, 10:42 PM**

Quote:

Ted White wrote:

Hi Tom,

So you're attaching the soffit frame to the decoupled walls and ceiling? Are you going to double drywall the soffit face?

You know, I didn't really think of that...I was planning on affixing 3/4" plywood to the soffit frame that would be directly attached to the wall/ceiling. Inside was going to house lights and the ductboard for my deadvent ventilation setup. Insulation was going to fill the remaining of the cavity, leaving just a little bit bare around the light housings.

Do you have another suggestion? Due to low ceiling clearance, I really don't have enough room to add something under the 3/4" ply that I planned on staining.

I guess I should forgo the ply and do double drywall/greenglue on the soffits instead?

What does everyone think? Is there another way to keep the 3/4" ply without compromising the integrity of my triple drywall/greenglue room or should I just return the ply I bought and DD/GG the soffits and paint them the same color as the ceiling?

Wait a minute...wouldn't the soffit still be decoupled since I built a true room within a room? I have separate ceiling joists and separate walls so the soffit would not be attached to any of the original basement walls or the floor above.

Now I'm confused! Please help.

**bpape** · **05-05-09, 05:50 AM**

You're fine. As long as you built the soffit framing after the room drywall and it's attached to the decoupling part of the structure, you'll not get any transmission. Yes - there is a bit of a potential for a triple leaf but you're so different that I don't see it being a large problem - not to mention it not acting like a sealed cavity due to all the penetrations for the lighting.

Insulate it well and you should be just fine. If you want it a bit better, you could swap MDF for plywood. Not a ton of mass difference but a bit. Certainly is harder to get to look like a smooth finish though.

Bryan

**Ted White** · **05-05-09, 08:30 AM**

#1 The soffit frame would be decoupled. That's good.

#2 If you're running ventilation in the soffit, you will need to have the face and bottom of that soffit double drywall or comparable. Not single drywall.

#3 If you want the lowest profile soffit, you need to reduce the framing material depth. You do this by substituting the first layer of drywall with OSB or ply. If the first layer of the soffit were 7/16" or thicker OSB, that would act as a frame. Assemble the soffit and then attach the drywall.

#4 Line the soffit with a lower density duct liner. The soundboard and foams are not as absorbent as you'd like.

#5 The holes for the lighting will feed sound into the duct. Not advised.

**bpape** · **05-05-09, 08:40 AM**

Ted

The HVAC ducting is in it's own MDF box for isolation already due to the lighting holes.

Bryan

**Ted White** · **05-05-09, 08:54 AM**

Oh the lights and ventilation are in separate soffit systems?

**bpape** · **05-05-09, 09:08 AM**

There is a separate MDF box inside the soffit framing for the HVAC to maintain isolation

Bryan

**Ted White** · **05-05-09, 09:12 AM**

Man, that is a of a good idea Bryan. So a chase inside the soffit. I love it!

**bpape** · **05-05-09, 09:16 AM**

I recommend that to almost all of my design customers who have to do soffit lighting. Sometimes it makes the soffits a bit larger but it's relatively easy, effective, and a great way to also get some nice bends in the ducting. I usually have them do duct board or duct liner inside the chase and then fluffy inside the rest of the soffit.

That also allows a single layer of drywall - not only for headroom purposes, but also to let it give a little extra bass absorption all the way around the room up in the wall/ceiling corners.

Bryan

**Ted White** · **05-05-09, 09:18 AM**

Very creative. Really

**tjambro** · **05-07-09, 10:42 PM**

Bryan and Ted, I'm glad "we", meaning you guys, had this conversation. I know Bryan did talk to me a while back about using mdf for the soffits but I guess I didn't understand fully and lost the significance of the dedicated mdf box over time. I thought the soundlock in conjunction with the ductboard and deadvent setup would be ok even with cans in the soffits. My latest plan de-volved into just having 3/4" ply over the 2x2's with the ductboard vent and lights sharing the same cavity.

Thanks for setting me straight guys! I don't have enough headroom to include 2" of ductboard (1" for top and 1" for bottom) within a 3/4" mdf box plus the 3/4" ply or drywall on top of that. I guess that's why a lot of people use veneer over the mdf shell? I really don't want to mess with veneer, I don't think I have the skills or patience to work with it.

Back when I was painting my ceiling I even thought to myself, why was I planning to put 3/4" finished ply over the soffit frames and stain them. I think it would be a nice accent on a smaller soffit in a larger room but in all reality, I want the soffits to not be all that noticeable.

Maybe I should scrap the finished ply and stand alone 2x2 framing altogether and build the soffits from osb and drywall as Ted described but make an extra vertical partition to separate the duct from the can lights. Perhaps I could line the duct with 1/2" Linacoustic to re-claim the height that I will lose due to the OSB/drywall face and bottom. I could still use 2x2's to secure the osb to the wall/ceiling and as furring strips along the vertical duct/can divider to attach the osb/drywall to the bottom.

For the vertical duct/can divider, could I attach mdf to the osb instead of drywall since it will be internal to the soffit?

How does this plan sound? Is there anything else I'm missing or not thinking of?

**bpape** · **05-08-09, 06:20 AM**

Separating them with the vertical will be OK. You should be using flex ducting which is somewhat self insulating already. The other cavity with the lights should be damped - just pay attention for spacing especially if they're non IC rated cans.

Bryan

**Ted White** · **05-08-09, 09:32 AM**

I would build the ply+drywall combo. Forget the 2x2 frame to max on internal volume and minimize the headroom loss.

Separate the soffit into dedicated duct and dedicated ceiling can containment.

Try and leave enough volume for the ventilation run to have enough absorption, or it won't work. Duct liner is your friend here. Abandon other materials.

**tjambro** · **05-08-09, 06:54 PM**

Quote:

bpape wrote:

Separating them with the vertical will be OK. You should be using flex ducting which is somewhat self insulating already.
Bryan

I can't use flex because it won't fit in the soffit. There's only 6" from the ceiling to the top of my door (not door frame, the door itself) and I really don't want a shallow soffit over the door and a taller one around the rest of the room. Plus the room is only 7'3 and the entrance to the room makes people walk under the soffits, so I want to keep them as shallow as possible.

**tjambro** · **05-08-09, 07:06 PM**

Quote:

Ted White wrote:

I would build the ply+drywall combo. Forget the 2x2 frame to max on internal volume and minimize the headroom loss.

Ted, I think this is a good idea, thanks for the suggestion. I like the idea of ditching the 2x2's to maximize headroom. I think I may go with osb+drywall as you recommended above. I may dip into that 10th pail of GG sooner than I thought.

Quote:

Separate the soffit into dedicated duct and dedicated ceiling can containment.

Would you recommend osb+drywall for this vertical divider or would a single piece of 3/4" mdf do the trick? If the osb+drywall is better, I'm not against doing that...

Quote:

Try and leave enough volume for the ventilation run to have enough absorption, or it won't work. Duct liner is your friend here. Abandon other materials.

Would 1/2" duct liner all around do the trick? I know 1" would be better but 1/2" would help minimize headroom loss.

**Ted White** · **05-08-09, 08:21 PM**

"I think I may go with osb+drywall as you recommended above."

I can send you schematics

"Would you recommend osb+drywall for this vertical divider"?

Yes. Less mass, but traded for damping.

"Would 1/2" duct liner all around do the trick"?

I would really try and shave elsewhere. Every 1/2" will help.

**tjambro** · **05-09-09, 05:22 PM**

Well, I changed my mind again...that's what happens when you are "winging it".

I don't want to speak for either bpape or Ted White but to me the common theme they both stress is isolation of the HVAC duct from the can lighting within the soffit. Once I get out of the, "I have a shell with 3 layers of drywall/GG and it doesn't matter what I do in the room" mode, it makes total sense to isolate the duct within the soffit. I looked back over my correspondence with bpape (he's my "sound guy" and has designed my sound treatments) and sure enough, he did mention isolating the HVAC duct from the can lights and he suggested mdf.

From that time on, some how I found an "easier" way to build the soffits without adding the middle vertical piece leaving the duct not isolated and I also decided to use 3/4" ply instead of mdf. Due to the large width of these soffits, I really don't want to accent the room with the ply, I think it's too much.

So, having said all that, my latest soffit revision is to build the soffit frame with 2x2's, with the can lights in the smaller section of the soffit and the 1" ductboard in the larger section. The ductboard will be isolated with 3/4" mdf and the finished sides of the soffit will have 5/8" drywall over the mdf. I will throw some GG in between the 2 layers for additional damping.

This does make my soffit a little higher than I would like and I will not be able to maintain the same height over the door. I will try to make it as inconspicuous as possible, but the section over the door will have to be a little smaller in height to allow the door to open and close. Fortunately, there will be no ductwork over the door in the theater side so that will help. There will be ductwork over the door in the soundlock so that will pose a challenge. We'll cross that bridge when we get there...remember, we're winging it!

Thanks again guys for all the advice, please keep the comments coming!

**tjambro** · **06-14-09, 03:43 PM**

I can't believe it's been a month since my last post. I'm progressing very slowly but hey some progress is better than no progress. I returned 74 of the 80 2x2's I bought from Lowes at $1.97 each. I returned them because they were very warped and too difficult to find some decent ones. I picked up 50 from my local lumber yard. I figured they would be more expensive but it turns out they were actually cheaper than Big Blue. I paid $1.49 each and not only are they straighter, they are closer to being an actual "2x2".

Here's a picture of my longest duct board length down the left side of my theater:

The can lights will be in the smaller section of the soffit with the pink fluffy stuff. The return ductboard is separated from the can light section with two 3/4" pieces of mdf with a layer of GG in between. After the mdf is complete I will apply GG and a layer of 5/8" drywall to complete the soffit.

Here's another view:

That square hole on the right is where the return vent will be exiting into my HVAC room. I will box the area off and the ductboard will exit through the hole into the HVAC room where I will built a dead vent. It will not connect to the main house HVAC...unless of course the dead vent doesn't work for me. I must say it was very, very hard to grab the reciprocating saw and cut through my 3 layers of sheet rock and GG. All my sound proofing is destroyed until I finish the dead vent setup.

Here's one more view with the first sheet of mdf on the bottom:

If you look where the mdf ends, you can see 3 beads of acoustical caulk I put along the 2x2 divider before putting up the mdf. Once I put up the mdf, I couldn't figure a good way to seal off the vertical center mdf from the two soffit chambers. So while installing the 2 vertical mdf pieces, I let them overhang the 2x2 bottom and used my router to make them flush with the 2x2. I'm hoping the 3 beads of caulk will ensure a good seal to the mdf bottom. I used many screws to pull the mdf up tight against the caulk and since caulk is oozing out the side, I'm hopeful that it will seal properly.

You can see I ran some romex through the soffit before putting the mdf up. There will be 3 cans in this soffit and 1 outlet in the bottom of my "dummy" column. When all is said and done there will be 6 5" cans in the soffits (3 on each side), 3 outlets (1 in each dummy column on both sides and 1 behind the screen), 3 4" eyeball cans in front of the screen and 3 4" cans behind the AT screen to light up the speakers. I still have more electric to run but it will not go through this soffit. I originally was going to run audio/video cables through the soffits but have since decided against that. My new plan is to run electric high (soffits) and audio/video cables low along the wall behind the fabric frames I will make. I will have lights in the riser to contend with and will have to work around the electric outlet in the dummy column but I figured it will be a lot easier to get behind the fabric frames which will most likely be velcroed to the wall then ripping down the soffits to add more audio/video cabling. I know many people use smurf tubing and I even bought some but since my equipment will be in the soundlock room, I don't want to leave an open tube connecting the theater and the sound lock room.

Once I finish these soffits, I will work on the smaller soffits in the sound lock/lobby room. I may see if I can get away with using less 2x2's in the sound lock. I wonder if I need to isolate the lobby cans from the ductwork?

**Space** · **06-14-09, 11:07 PM**

Hi Tom! Just wanted to drop in and say "Hi Tom"! This is going to be one of a fine job, when it is completed because you are not cutting corners or rushing or all the other things people seem to do.

You must have a big screen TV in another room?

Looking forward to what you and the Misses have picked out for the finish...should be fun!

Brien

**Space** · **06-14-09, 11:07 PM**

I said "one H E C K of a fine job"!

**tjambro** · **06-14-09, 11:51 PM**

Quote:

Space wrote:

Hi Tom! Just wanted to drop in and say "Hi Tom"! This is going to be one h e c k of a fine job, when it is completed because you are not cutting corners or rushing or all the other things people seem to do.

Thanks Brien, I appreciate the encouragement. I do at times get lazy and sometimes need a swift kick in the butt, so that is now your official job...kick me in the butt once in a while to get me moving.

The 'ole wallet has been hit pretty hard lately so I have to build up more funds before I can buy any more materials/equipment so there's really no rush.

Quote:

You must have a big screen TV in another room?

Actually, I have no big screen in another room but I knew I would go insane without being able to watch movies. It was very hard for the first few months without a theater (sold the last one with the house) but I came up with this ingenious solution:

As posted early on in this thread, I present to you "Ambrosio's Drive-In Theater"...aka Xbox360 driving cabinet:

You can't see from this picture, but there's a 26" 1080p flat panel in there and the tips of my fingers can touch the screen when I am sitting in the '05 Neon car seat that I picked up at the junk yard...ahem, excuse me...Salvage Emporium.

There's a 5.1 HTiB with the itty bitty sub sitting right behind the car seat. Not IB quality, but not bad...for one...the misses is on her own.

At first, I was playing Forza 2 and watching movies, but ever since I bought and hooked up the Popcorn Hour Media player up to the flat panel, I had to pull the Xbox optical audio cable and haven't been switching back and forth like I thought I would. I currently have about 400 blu rays ripped to my unRaid server that I stream to the PCH. Works very, very well. So well that I have scrapped my HTPC from the previous theater.

Thanks for making me dig up that old picture. It makes me feel like I have done a lot since then...wow...I miss that paneling!....NOT!!

Quote:

Looking forward to what you and the Misses have picked out for the finish...should be fun!

Once I get the soffits done, I will have to consider that more...the wife says I can do it any which way I please which is great! Even with all their limitations, having a basement is so cool, isn't it?

I am leaning toward a very simple, clean layout. I like the fancy trim work and colors that some do, but they are too distracting while watching movies...at least for me. In my previous theater, the sconces and movie posters reflected light and drove me crazy...hence neither in this build. Since I will have a lobby this go round, I will put some lit movie posters in the lobby. As of now, I am planning to do the theater in GOM Anchorage #2045 (Cobalt) with a possible #2085 (Thistle) accent. Speaker columns will be finished birch stained black and the soffits/ceiling painted black. Theater seats most likely black. The lobby will have a bolder blue, most likely GOM Anchorage #2094 (Lapis). Both rooms will have fabric frames with beveled edges. The theater will be treated for sound and the lobby will only have fabric frames for looks, there will be no sound treatments in that room.

Oh, 7.1 speakers will all be DIY with 4 18" Fi IB drivers behind the screen.

**tjambro** · **06-15-09, 12:01 AM**

Space, here's another slightly better picture of the "drive-in":

This is also an old picture but at least you can see the screen a little better. It's funny how my nephews abandoned the "state of the art" X-box 360 driving cabinet with 5.1 surround and force feedback to play a game of Galaga circa 1981...

Spoiler

**Ted White** · **06-15-09, 09:06 AM**

Hey Tom,

Looking great. That insulation in the lighting compartment won't be too compressed, will it?

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